1. computergeek123

2. Lime

Alternate Interior angles are congruent when lines are parallel. Use Angle Addition Postulate.

3. Lime

\[m \angle ABD+m \angle CBD=m \angle B \]

4. Lime

\[\angle B \approx \angle D \]

5. Lime

Or \[\angle A \approx \angle C\]

6. Lime

I'm guessing you might have figured that out yourself. The key phrase is 'Alternate Interior angles are congruent when lines are parallel.'

7. computergeek123

yeah. haha So like what else do I need to write to prove they are congruent?

8. computergeek123

I searched all through the lesson and I can't find where they say Angles. I only do the sides! ?

9. Lime

It's a property of parallelograms. That statement is really enough proof as it is. I would back that statement up with the diagram and equations; if the question pushes for more information.

10. computergeek123

SO write "Alternate Interior angles are congruent when lines are parallel."??

11. Lime

Opposite angles are congruent because correspondent angles on congruent triangles are congruent. Yes, Alternate Interior angles are congruent when lines are parallel. The question is referring to angles.

12. computergeek123

Thank you.

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